The present invention relates to apparatus for the detection of vibration in rotating machinery.
Rotating machinery vibrates at a level dependent upon wear and imbalance in the rotating parts, assuming constant operating conditions. It is possible therefore to use vibration detection as a means of monitoring the mechanical condition of rotating machines and anticipate impending failures. Detection apparatus may be designed automatically to operate an alarm when the vibration has reached a certain predetermined level.
Such automatic alarm systems must, however, be insensitive to extraneous interference which could activate the alarm. Common mode interference, such as noise, can be reduced by means of bandpass filters tuned to the vibration frequency of the machine under test. Series mode interference in the form of transitory pulses can be discriminated against by introducing a low-pass filter in the path of the vibration signal.